Introduce charm.v5-unstable.

[frankban]

This mechanical branch updates the charm package to the
v5-unstable version. The legacy charm store code is
adjusted as required.
This is a preparatory work for the migration to the new
charm store API v4.

(Review request: http://reviews.vapour.ws/r/1236/)

[cmars]

$$merge$$

[jujubot]

Status: merge request accepted. Url: http://juju-ci.vapour.ws:8080/job/github-merge-juju

[jujubot]

Build failed: Generating tarball failed
build url: http://juju-ci.vapour.ws:8080/job/github-merge-juju/2642

[frankban]

This failure seems due to missing charm.v5-unstable testing dependencies in the dependency file.
Testing dependencies are not included transitively in godeps.
This could be solved by a temporary workaround, e.g.

var _ = charmstore.NewServer

in a testing package.
We are going to import charmstore.v4 for tests anyway.

[cmars]

@frankban You'll need to add the missing dependencies to Juju's dependencies.tsv in order for this to land. Use godeps -t $(go list $PKG) where $PKG is the transitively included package with the test dependencies (there might be more than one).

[frankban]

$$merge$$

[jujubot]

Status: merge request accepted. Url: http://juju-ci.vapour.ws:8080/job/github-merge-juju